Speed of sound, speed at which sound waves propagate through different materials. In particular, for dry air at a temperature of 0 °C (32 °F), the modern value for the speed of sound is 331.29 metres (1,086.9 feet) per second. The speed of sound in liquid water at 8 °C (46 °F) is about 1,439 metres (4,721 feet) per second.

In the form of equation (141), Bernoulli’s law may be used to calculate the speed of sound in gases. The argument is directly analogous to the one applied in the previous section to waves on shallow water—and, indeed, the diagrams in Figure 6 can serve to illustrate the argument here too, if they are regarded as plots of gas density (or else of pressure or temperature, which go hand in...

A sound wave is a series of longitudinal compressions and expansions that travels through a liquid at a speed of about one kilometre per second (0.62 mile per second), or about three times the speed of sound in air. If the frequency is not too high, the compressions and expansions are adiabatic (i.e., the changes take place without transfer of heat) and reversible. Conduction of energy from the...